Lifting magnet



Dec. 20, 1949 A. E. LILLQUIST LIFTING MAGNET 4 Sheets-Sheet l Filed May 29, 1944 LIFTING MAGNET Filed May 29, 1944 4 Sheets-Sheet 3 5 d.4 4 As 3 56 Dec. 20, 1949 I A. E. LILLQUIST 2,491,743

LIF'IING MAGNET Filed May 29, 1944, I 4 Sheets-Sheet 4 Patented Dec. 20, 1949 UNITED STATES PATENT OFFICE LIFTING MAGNET Arvid E. Lillquist, Milwaukee, Wis, assignor to Cutler-Hammer, Inc., Milwaukee,- Wis., a corporation of Delaware Application May 29, 1944, Serial No. 537,891

2 Claims.

This invention relates to electromagnets and While not limited thereto is particularly applicable to magnets for lifting and handling articles of small magnetic metal content as compared to their weight such as filled metal cans.

It is common practice in food canning plants to place the food material in metal cans and then stack the cans on end and in definite layers within baskets for a cooking operation. Stacking of the filled cans within the cooking baskets and removal therefrom upon completion of the cooking operation has heretofore been carried on manually. However, it is desirable to perform these handling operations and also other can handling operations by means of a lifting magnet, and the present invention has among its objects to provide an improved magnet for this purpose.

More specifically the invention has among its objects to provide a lifting magnet which is of a diameter to fit within the cooking baskets commonly employed in food canning plants; which is capable of picking up and securely holding filled cans on end and in a single layer for loading and unloading of the cooking baskets, and

which is constructed to render the same waterproof.

Another object is to provide a lifting magnet of the aforesaid character which is exceedingly simple and rugged in construction, reliable in operation and of large lifting capacity for its size and weight.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be described, it being understood that various modifications may be made in the embodiments illustrated without departing from the spirit and scope of the appended claims.

In the drawings,

Figure 1 is a top elevational view of a lifting magnet embodying the invention;

Fig. 2 is a side elevational view thereof;

Fig. 3 is a fragmentary bottom view on an enlarged scale of the working face of the magnet shown in Fig. 1;

Fig. 4 is an enlarged fragmentary sectional view on line 4-4 of Fig. 1;

Fig. 5 is an enlarged view illustrating certain Fig. '7 is a fragmentary sectional view on line 3 welded to the upper face thereof. The upper face of said magnet frame is also provided with a pair of terminal boxes 4 and 5 having flexible leads 6 and 1 extending outwardly therefrom, and as hereinafter set forth the magnet is provided with an energizing winding which is formed from a continuous piece of strap copper and is connected within the terminal boxes to said leads.

As shown in Fig. 4, magnet frame I comprises a circular top plate 8 having a plurality of pole projections on the underside thereof including a center pole 9, an outer pole ring In and a plurality of intermediate pole rings H. Center pole 9 is cylindrical in form and is secured by a weld l2 within a center recess in the underside of plate 8. The outer pole ring Ill and intermediate pole rings ll comprise strips of sheet steel which are rolled into cylinders of various diameters. The strip forming outer pole ring 10 has its ends welded together as shown at l3 in Fig. 3, and the same surrounds top plate 8 and is secured to the periphery thereof by a continuous weld l4 shown in Fig. 4. The underface of top plate 8 is provided with a series of concentric grooves l5 for receiving the upper edges of intermediate pole rings H, and as shown in Fig. 3 each of said in-' termediate pole rings has its upper edge secured to said top plate at a plurality of points by tack welds I6 which are located within radially disposed grooves I"! in the underface of said plate. Also each of the intermediate pole rings II has its ends spaced apart to provide a gap 18 and said rings are arranged so that the gaps l8 are staggered, as shown in Fig. 3.

The intermediate pole rings I I provide a series of annular coil spaces 20 between the center pole 9 and outer pole ring In. As will now be set forth, the magnet is provided with an energizing winding 2| which is designed to be supplied with current of low voltage, as for example 24 or 32 volts. Said winding comprises a continuous piece of strap copper which is wound outwardly from the center pole 9 to provide a coil section 22 in each of the coil spaces 20 and the same is provided with insulated end terminals 24 and'25 which extend upwardly through openings in top plate 8 into the terminal boxes 4 and 5, respectively. The coil sections 22 are formed by winding the strap material flatwise in the form of a spiral with a strip As shown in Fig. 4, each of the coil spaces la contains a pair of mica insulating washers 21 and 28 for insulating opposite ends of the coil section contained therein. Also as shown in Figs. 4 and 5, inner pole 9 is surrounded by an insulating cover 29, outer pole ID has an insulating cover 36 on the inner surface thereof, and each of the intermediate poles H has an insulating cover 3| which extends over its inner and outer surfaces and over the side edges of gap l8. The coverings 29, 38 and 31 are preferably formed of insulating material such as sheet mica.

As shown in Fig. 4, the several pole projections 9, l0 and l 1 project downwardly beyond the lower ends of their associated coil sections 22 and the spaces provided by the projecting ends of said poles are filled with a covering of hardened plastic material 33. The plastic material 33 adheres to the sides of the several pole projections and acts to seal and support the several coil sections 22 within the coil spaces 20.

As hereinbefore stated, winding 2| is provided with insulated end terminals 24 and which extend upwardly through openings in top plate 8 into the terminal boxes 4 and 5, respectively. The

terminal boxes 4 and 5 are of water-tight construction, and as shown in Fig. 4 each of the same is provided with a housing 34 Which is secured to the upper face of top plate 8 by a weld 35. The flexible leads 6 and 1 associated with the terminal boxes are connected to the winding terminals 24 and 25, respectively, through the medium of insulated binding post assemblies 36 which are mounted within the housings 34,

In connection with. the foregoing it should be noted that the above described magnet is adapted r.

to lift and hold articles of small magnetic metal content as compared to their weight, and is particularly adapted for the handling of filled metal cans in food canning plants. .The above described pole and winding arrangement provides a multiplicity of narrow circular fields on the face of the magnet. These fields are shallow and are distributed over the entire face of the magnet whereby the magnet is adapted to lift filled cans,

on the end and in a single layer, either from another layer of cans or from the bottom of a steel cooking basket as is required in canning factories.

As hereinbefore stated, the aforedescribed magnet is designed for energization by current of relatively low voltage. However, the same may be modified as shown in Figs. 6 and 7 for energization by current of higher voltage, as for example 110 volts. For this purpose the coil spaces 28 in the magnet frame are provided with separate annular coil sections 38 which are formed from round insulated wire. Each of said coil sections is provided with an inner terminal 38 and an outer terminal 38*, and the terminals of the several coil sections extend upwardly through a radially disposed slot 39 in top plate 8 into an elongated terminal box 40 which is welded to the upper face of said plate. Terminal box 40 is provided with flexible leads 4| and 42 which are 4 connected within said box to a pair of insulated binding posts 43 and 44. Also said terminal box contains a pair of insulating terminal blocks 45 and 46 which are disposed on opposite sides of the slot 38. Each of said terminal blocks carries a series of terminal plates 41 and the terminal plates associated with terminal block 45 are connected to inner terminals 38 of the several coil sections, while the terminal plates associated with block 46 are connected to outer terminals 38 of said coil sections. The several coil sections 38 are connected in series relation between the binding posts 43 and 44 by leads 48 and 49 and jumper connections 50 associated with the terminal plates 41. Also the terminal plates 41 are interconnected by the jumper connections 50 so that the direction of current in adjacent coil sections 38 is in opposite directions for alternate north and south polarity of the several pole projections.

What I claim as new and desire to secure by Letters Patent is:

1. In a lifting magnet, a magnet frame comprising a horizontally disposed circular top plate having a plurality of pole projections on the under side thereof, certain of said pole projections comprising cylinders formed of sheet steel which are concentrically disposed and of different diameters to provide a series of annular coil spaces therebetween, said cylinders also having their end portions spaced apart to provide gaps therein, and a winding formed of strap copper having insulated coil sections mounted in said coil spaces, and connecting portions therebetween which are located within said gaps.

2. In a lifting magnet, a magnet frame comprising a horizontally disposed circular top plate having a plurality of pole projections on the under side thereof, certain of said pole projections comprising cylinders formed of sheet steel which are concentrically disposed and of different diameters to provide a series of annular coil spaces on the under side of said top plate, said top plate having,

circular grooves formed on the under side thereof for receiving the upper edges of said cylinders and also having radial grooves intersecting said circular grooves and said cylinders being secured to said top plate by welds located within such radial grooves, and a magnet winding having insulated coil sections mounted within said coil spaces.

ARVID E. LILLQUIST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,180,457 Walker Apr. 25, 1916 1,554,236 Simmons Sept. 22, 1925 1,603,497 Simmons Oct, 19, 1926 1,608,677 Sederholm Nov. 30, 1926 1,704,783 Bing Mar. 12, 1929 1,853,471 Storch Apr, 12, 1932 1,970,922 Simmons Aug. 21, 1934 2,086,164 Karasick July 6, 1937 2,138,864 Karasick Dec. 6, 1938 2,165,582 Scofield July 11, 1939 OTHER REFERENCES American Machinist, of Feb. 16, 1911, page 312, article on Magnetic chucks. 

